Dental handpiece wrist-joint guard



, l 632 860 June 21 1927. G' A' TERRY 9 9 DENTAL HANDPIECEVWHST JOINT GUARD Patented June 21, 1927.

UNITED ,STATES narrar caries.

GEORGE A. TERRY, OF' BUFFALO, NEW YORK.

nENTAL'HnNnPrscE Waise-JOINT GUARD.

Application filed vAugust 5, 1925. SeralNo. 48,295.

body of the patient. The objecty of this in vention isto provide a guard tor this purpose which is simple and inexpensive, capableof being readily attached to and removed from the Wrist joint of the hand piece and which effectively proteetsboth the operator and the patient against injury and annoyance by the driving belt. To that end this guard consists oftvvo guard disks adapted to. engage with retaining heads at opposite ends of thepintle which pivo-tally supports the belt guide pulleys on the Wrist joint, and a cross piece connecting the guard disks and extending across one side of the Wrist joint.

In the accompanying drawings Figure 1 is a side elevation ot a dental hand piece having its Wrist joint equipped with my improved guard.

Figure 2 is a similar view, on an enlarged scale, of the wrist joint provided With the guard. Figure Bis a vertical section of the same taken on line 3-3, Fig. 2.

Figure 4 is a perspective view of the Wrist joint equipped with the guard.

Figure 5 is a. similar vien7 of the guard detached.

Figure 6 is a fragmentary vertical section similar to Fig. 3 and showing a modification of the means for retaining the guard in position.

` Similar characters of reference indicate like parts in the severalfigures ot the draw-y ings.

The numeral 10 representsthe rotary dental hand piece upon the ,trout end ot which` a Suitable tool is adapted to be mounted and the rear end of which is provided With a driven pulley 11 around which the turn ot a driving belt 12 is adaptedto pass. This hand piece is support-ed on the dental engine stand by an articulated bracket which includes a wrist joint which is coupled with the hand piece and arranged close to the wrist of the operator when the hand piece is in use. This Wrist joint may consist ot front and rear arms 13, 14 which are pivotally connected With eachother by a transiferse Wrist pin 15 and said joint arm having a bearing 16 on which the hand piece is journaled While the rear arm is connected in any suitable manner with the stand ot' the dentalengine.

Qn oney side of the Wrist .pinfthe front Wrist joint arm is provided ivitha pintle v17 extending transversely through this arm and projecting beyond the opposite sides thereof.

.Upon the reduced ends oi the pintlel are pivotally mounted guide pulleys 18 around which the stretches of the driving belt pass on the Way to and from the driven pulley of the hand niece. These pulleys are retained on the en s of the pintle by kretaining heads 19 overlapping the outer sides of the pulleys and each having a shank 20 which is secured in a recess in the adjacent end of the pintle.: This shank may eitherl have a smooth terior and be held frictionally in the respective recess of the pintle, as shown at the right of 3, or the samemay be threaded eXn ternally and engaged with a corresponding internal thread in the respect-ive recess o t the pintle, as shown at the lett of Fig. 3. ln the preferred construction Ythe retaining heads are of spherical form, as shown in this ligure.

My improved guard `for the Wrist joint is` generall of U-form and consists o two disks or side plates 21 which are adapted to be arranged parallell adjacent to the outer sides .of the guide pulleys and a cross piece or bar 22 arranged transversely oit the wrist joint on the front or outer side thereot1 and connected. at its oppositeI ends with the corresponding ;tront edges of the guard disks. The inner sides of the guard disks are provided'ivith spherical sockets 23 which receive the spherical heads on the pintle andthe marginal part of each disk is ot a larger diameter than the adjacent pulley and turned inwardly slightly -ivithout, however, extending across the plane ot the outer side 'of this pulley, as shown in Fig. 3 at 2li, tl'lereby preventing this pulley 'trom coming in contact,- ivith the hand of the operator or the body oit the patient, and also preventing the driving belt from becoming caught between the guard` disks vand the guidezpulleys.

The guard disks and cross bar are pretore ably constructed integrally from a Asingle sheet otresilientmetal, such as sheet steel, so as to necessitate springing the disks apart in order to permit of engaging their spherical socketswith the spherical retaining-heads on the pintle after which the resilience of the metal operates to hold the guard frictionally on the pintle heads and in the proper position to protect the operator` and patient j the driving belt and thereby permit the arms of the wrist joint to swing freely the maxi- K central part of its upper end and lower edges with finger pieces 25, 25 which permit of` mum extent without liability of the cross bar interfering with the driving belt. In order however, to prevent a circumferential" displacement of the guard the central part of the cross bar is engaged with the flat'front side `of the front wrist joint arm.' For convenience in `removing the guard from the wrist joint the cross bar is provided on the taking hold of the guard withthe fingers and drawing the same laterally with sufficient force toV disengage the sockets of the disks from the retaining heads and detaching the guard `from the wrist joint when this is required for inspection, adjusting, lubricating or repairing. i v

In the modification shown in Fig. 6, the retaining heads 19a which overlap the pulleys 18 and retain them onthe reduced ends of the pintle 17 in the same manner as in the preferred construction, are of tapered or conical form and the two disks or side plates 21 of the guard which are adapted to be1 arranged adjacent the sides of the pulleys are eachprovided on their inner sides with conforming or .conical sockets 2N adaptedto receive the respective head. s Byinaking the retaining heads andthe sockets of the guard disks of conical form rather than sphericala more reliable engagement between these parts is obtained, and the guard is less likely to Vaccidentallyslip off. lOnly one retaining head is shown in Figure 6, but it is to be understood that the other head is also conical and that the wrist joint is in other respects similar to the preferred construction.

Owing to the guard being made of one piece the same is exceedingly simple in con-` struction andit can. be produced at low cost.

Y j It lies very'close to the wrist joint when in use `without interferingwith any working partsand by reason of its frictional mounting oufthe wrist jointthe same can be veryV j joint having a pintle and belt guide pulleys 4the outer sides of said pulleys an to resil- `and provided on their inner sides withconimounted von said pintle, said guard compris- Y ing guard disks adapted to be arran ed along iently engage the opposite ends of the pintle, and a cross piece connecting the disks.

e 2. A guard for a dental hand piece wrist j i joint having a pintle, belt guide` pulleys journaled on opposite ends of said pintle, and heads on the ends of the pintle overhanging the` outer sides of said pulleys,rsaidv guard comprising `guard disks arranged lad acent tothe outer-.sides of said pulleysan provided ontheir inner sides with sockets adapt-` ed to receiveasaid heads, and across piece connecting corresponding edges of said disks.

' 3. A guard for a dental .hand piece wrist. joint having a pintle, belt guide pulle s journaled on opposite ends of said pint e, 7. Y'

and conical heads on Vthe ends ef the pintle overhanging the outer sides of said pulleys, said guard comprising guard disks arranged` adjacent tothe outer sides of said pulleys cal sockets adapted `to receive saidv heads, and al cross pieoe connecting corresponding edgesof said disks. L i J 4. A. guard for a dental hand piece wrist joint having pintle, belt `guide pulleys journaled on opposite ends `of said pintle and heads on the ends of tliepintleoverhanging the outer sides of saidpulleys, said guard comprising guard disks arranged adjacent to the outer sides of said pulleys and provided on their inner sides with sockets adapted to receive said heads, and a cross piece connecting corresponding edges of said disks, `the end portions of said cross piece being comparatively narrow andthe central piece. j

5. A guard for a dental hand piece wrist joint having a pintle, belt guide pulleys journaled on opposite ends ofsaid pintle, 100

and heads on theends of the pintle overhanging the outer sides of said pulleys, said guard comprising guard disks varranged adjacent to the outer sides of said pulleys and provided on theirv inner 'sides with sockets 105 adapted to receive said heads, and a cross piece connecting the corresponding edges of said disks, the central pai-tof said cross piece beingl provided on its upper and lower edges with finger pieces, and said cross piece and 110 disks beingconstructed integrallyfrom a resilient sheet of metal.

, In testimony whereof I aix my signature. i

GEORGE A. '"iERRY,

part thereof being provided with a finger 

